The present invention relates to a microwave oven, and more particularly, to a temperature detecting unit to be incorporated in the microwave oven for detecting the temperature of the object to be heated.
It is known to use a temperature detecting unit in a microwave oven for electrically detecting the temperature of the object to be heated in the oven. The temperature detecting unit of the convention type includes a probe portion including a handle for holding and capable of being inserted, at one end thereof, into the object and a cable extended from the other end of the probe to an inside wall forming a heating cavity in the microwave oven. According to the conventional type of the temperature detecting unit, the cable is normally constructed with a comparatively thick and stiff wires so as to increase shock resistance of the temperature detecting unit and to strengthen the connection of the cable at the opposite ends thereof with respective connected elements. Moreover, such stiff cable hinders efficient handling of the temperature detecting unit particularly when the probe must be used at positions where it is necessary to stretch out the cable, and even when the probe is inserted to the object somehow with the cable stretched, the temperature detecting unit is comparatively unstable in its position, and thus, the unit may easily fall off from the applied position, whereby the probe, especially a temperature detecting element provided therein, may be damaged, or otherwise, there may be produced an undesirable spark discharge between the probe and the inside wall of the heating cavity. Such spark discharge may cause some flaw on the inside wall or on the probe, not only spoiling the appearance of the oven, but also giving rise to insanitary condition if fragments of food material and the like should get in the flaw. On the other hand, if the cable is constituted with thin wires, there is such a disadvantage that the cable is apt to be damaged or broken particularly at opposite ends thereof connected to the probe and the inside walls of the heating chamber. Furthermore, in the arrangement as described above, convenience in actual use is commonly sought after, for example, by automatic change over from cooking by the temperature detecting unit to that by timer means through selective insertion and withdrawal of the probe of the detecting unit into and from the objects to be heated, and therefore, should the cooking be carried out by the timer means with the temperature detecting unit carelessly left in the heating chamber due to handling difficulty of the detecting unit as described above, the detecting unit is readily subjected to burning. Accordingly, development of a temperature detecting unit easy to handle, and yet having sufficient durability has been strongly damanded up to the present.